The field of the invention is computer methods for monitoring and forewarning of condition changes, including critical events, such as structural failures in structures such as bridges, buildings, dams, tunnels and other civil structures. The technology can also be applied to large manufactured items such as airplanes, and mining and construction equipment.
Hively et al., U.S. Pat. No. 5,815,413, disclosed methods of forewarning in medical patients, and also described the applicability of nonlinear techniques to monitor machine conditions using accelerometer data. Hively et al., U.S. Pat. No. 6,484,132, provided improvements in these methods of forewarning. Hively, U.S. Pat. No. 7,139,677, introduced a composite measure of dissimilarity (C). This composite measure of condition change (C) was calculated from the sum of the four normalized measures of dissimilarity, including U(χC2) and U(LC) from the connected phase space and including U(χN2) and U(LN) from the non-connected phase space. This was developed further across multiple data channels in Hively, U.S. Pat. No. 7,209,861, where the composite measure of dissimilarity, (C), was used to provide an end-of-life forewarning factor (G).
Welch et al., U.S. Pat. No. 6,460,012, disclosed an apparatus for the detection of an indicator of imminent failure due to crack growth in structural elements. The apparatus included sensors for sensing physical data factors, a processor for computing a relationship between the physical data factors and an indicator of the failure event.
Hodge, U.S. Pat. No. 6,012,337 discloses physical integrity monitoring of bridges and buildings using optical sensors to sense directional movements of the structures in a plurality of axes.
Strasser et al., U.S. Pat. No. 6,292,108, discloses a data acquisition system for collecting data from a plurality of sensor units for sensing damage in civil structures resulting from earthquakes, for example. Strasser et al. discloses the use of accelerometers as sensors for collecting mechanical vibration data. Di Marzio, U.S. Pat. Pub. No. US2004/0078170 discloses a system with sensors disposed on a structure, a central repository and a mesh network for communicating the data from the sensors to the central repository.
The present invention improves over the prior art by providing an improved method of processing sensor data collected from sensors on a physical structure to provide a forewarning of a critical event signaling deterioration or failure of the structure.